Project 5: Therapeutic human monoclonal antibodies for treatment of hantavirus cardiopulmonary syndrome. (J. Botten, Project Leader). Treatment for HCPS is currently limited to supportive care. Ribavirin, while effective at restricting viral replication in vitro, has not conclusively been shown to be efficacious in alleviating HCPS severity. Administration of immune plasma from recovered HCPS patients to deer mice has been shown to protect rodents from viral challenge. This aim will test the efficacy of passive administration of neutralizing antibodies by generating a panel of human Fab fragments capable of in vitro neutralization. The long range goal of the proposal will be to develop a bank of human monoclonal antibodies which can be given therapeutically for the treatment of hantavirus infections.